Accounts and Notes Receivable and Credit Quality of Notes Receivable (Allowance for Doubtful Accounts Receivable) (Details) - Notes receivable - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 5.9	$ 5.6
Charge-offs	(2.1)	(0.1)
Recoveries	(0.5)	0.0
Provision	6.4	2.6
Ending balance	9.7	8.1
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment [Roll Forward]
Beginning balance	5.9	5.6
Charge-offs	(2.1)	(0.1)
Recoveries	(0.4)	0.0
Provision	5.2	2.6
Ending balance	8.6	8.1
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment [Roll Forward]
Beginning balance	0.0	0.0
Charge-offs	0.0	0.0
Recoveries	(0.1)	0.0
Provision	1.2	0.0
Ending balance	$ 1.1	$ 0.0